This invention relates to a geographic information system, in particular, a geographic information management method which enables an object landmark to be found by referring to previous data even if the landmark has disappeared.
Conventionally, updating to the latest data is considered as being important in the management of map data of a geographic information system. Therefore, once map data is updated, old map data is discarded. For example, Japanese Patent Application Laid-Open No. 2003-330360 (hereinafter, referred to as Patent Document 1) discloses a method of managing buildings on a map and attribute data in time series. The disclosed method allows a configuration and attributes of a building at a designated specific time to be retrieved. However, when a time at which an object building existed is unknown, it is difficult to retrieve the object building over different periods of time.
Japanese Patent Application Laid-open No. 2003-157287 (hereinafter, referred to as Patent Document 2) discloses a method of relating a reference point added in a graphic with attribute data. When the attribute is modified, new attribute data is related with the reference point for which the attribute is modified. As in Patent Document 1 described above, it is still difficult to perform retrieval over different periods of time with this method.